Explosive composition



Patented Feb. 14, 1928 UNITED STATES PATENT OFFICE.

WALTER O. SNELLING AND GUY A. RUPP, 0F ALLENTOWN, PENNSYLVANIA, AS-

SIGNORS TO TROJAN POWDER COMPANY, OF NEW YORK, N. Y. A CORPORATION OF NEW YORK.

EXPLOSIVE COMPOSITION.

No Drawing. Application filed July 17,

Our invention relates to improvements in explosive compositions, and part cularly in explosive compositions containing ferrosilicon. p

The use of ferrosilicon as an ingredient of explosive compositions was known prior to our invention, and explosives containing comparatively large percenta es of ferrosilicon were commercially ma e for a time, but their manufacture has since been discontinued, as these explosives were found to possess too low efliciency to meet existing competitive conditions in the explosives industry.

\Ve have found that the use of coniparalively large percentages of ferrosilicon, particularly in low grade explosives, is undesirable, and that proper elliciency of explosive action is not obtained. "We have discovered further that the efficiency of ferrosilicon as an element of explosive mixtures drops olf rapidly" as increasing quantities are used, and that a very small amount of ferrosilicon forms a highly elficient and very desirable constituent of an explosive composition, whereas this substance when used in larger amounts forms an undesirable constituent. This is probably due to the great alfinity of fei-rosilicon for oxygen, which causes it, when present in large quantities, to rob the other combustible constituents in the explosive of the oxygen necessary for their combustion, producing iron oxide and silicon dioxide in the products of combustion of the explosive instead of the as-forining carbon monoxide and carbon dioxide that would otherwise be produced. As explosives owe their usefulness and their elliciency to the sudden production of a large volume of gas at. the instant of detonation, it will be evident that any constituent that modifies the explosive reaction by absorbing available oxygen with the production of a solid, nonvolatile product will ordinarily reduce the QlfiClGTICy of the explosive of which such material is a constituent, but we have found that within certain small percentage limits, the amount of heat evolved in the oxidation of ferrosilicon enables this material to be used to advantage, although when used in any quantity beyond the eflieient limits which vwe have discovered, the use of the material leads to a reduction in gas volume 1926. Serial No. 123,255.

and to a marked falling off in the efficiency of the explosive. 7

We have further discovered that the use of small percentages, say from 1 to 4% ol ferrosilicon, is of particular advantage in connection with explosives containing nitrostarch, and more particularly in explosives whose sensitiveness is so low that they will not normally lire from the action of the detonator. although they fire with high efiiciency from the action of a booster charge.

As an example of an explosive made in accordance with the present invention, we may take 63.49 parts of sodium nitrate and 10 parts of ammoniumvnitrate, and coat these two salts jointly with 8.16 parts of trinitrotoluene, thus obtaining 81.65 parts of a mixture of 90/10 amatol and sodatol. The coat-v ing operation may be performed by heating, the,,t\vo salts to a temperature of approximately 100" adding the trinitrotoluene, stirring until the molten trinitrotoluene has thoroughly coated the two salts, and then cooling the resulting mixture.

To the 81.65 parts ot- 90 10 tlll'lillOl and sodatol made as described above, we add .15 parts of mineral oil, .20 parts of sodium bicarbonate. 3 parts of feti'osilicon, 6 parts of cornmeal, and 9 parts of nitrostarcb. The resulting mixture is an explosive of great strength. but relatively insensitive, and vto secure detonation the use of a strong priming charge is desirable.

The invention, however, is not limited to explosives of low scnsit-iveness, and as an example of an explosive which is of higher sensitiveness and which makes use of the same. principle of employing a relatively small amount of ferrosilicon. we may take 51.93 parts of ammonium nitrate and coat it with 3.32 parts of trinitrotoluene, thereby obtaining 55.25 parts of 94/6 amatol. The aniatol is mixed with .25 parts of a mineral lubricating oil, .20 parts of zinc oxide, 3.30 parts of cornmeal, 2 parts of ferrosilicon. 25 parts of sodium nitrate, and 14 parts of nitrostarch. This provides an explosive of great strength and good sensitiveness.

The general composition of an explosive made in accordance with this invention ma v vary in large degree, the essential feature of the invention residing in the use of an amount of ferrosilicon only sulficient to give the desired additional heat to the products of ex )losion, butinsufiicient in amount to materially reduce the gas volume of the resulting explosive by the absorption of available oxygen in the formation of the nonvolatile oxides of iron and silicon. 'e have obtained the best results with quantities of ferrosilicon smaller than 5%, and in general prefer to use from 1%,- to $75 of this ingredient.

Our explosive also as stated above pr =1- erably contains nitrostarch. and the amount thereof in general may vary from 5% to about 2092. The remainder of the explosive composition may be ammonium nitrate, sodium nitrate or their equivalents, amatol and sodatol, together with carbonaceous material, such as cornmeal, wood pulp. ground vegetable ivory or like material, and such other ingredients of common usage as may be found desirable.

\Ve claim:

1. An explosive composition comprising nitrostarch and ferrosilicon, said ferrosilicon being present in amounts up to 5%.

2. An explosive composition containing from 1% to 4% of ferrosilicon and from 5% to 20% of nitrostarch.

An explosive composition of low sensitiveness comprising nitrostarch and ferrosilicon, said ferrosilicon being present in amounts up to 5%.

4. An explosive comprising nitrostarch, ferrosilicon, {llIlIIlOIllllll'l nitrate and carbonaceous material. said ferrosilicon being present in amounts up to 5%.

5. An explosive composition comprising nitrostarch and ferrosilicon, the amount of nitrostarch being at least four times the amount of the ferrosilicon, and the combined amounts of ferrosilicon and nitrostarch being, less than one-fourth of the total quantity of the explosive mixture.

\VALTER O. SXELLING. GUY A. RUPP. 

